Propeller



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, July 25, ,1933.- A. Y. DODGE lPROPELLER Filed June 16, 19:50

July 25, 1933.

A. Y. DODGE` PROPELLE'R 2 Sheets-Shet 2' Filed Jun 16, 1930 ma@ v z T. f u my amy diei Patented July 25,1933

UNITED STATES PATENT I OFFICE ADIEL Y. DODGE, 0F SOUTH BEND, INDIANA, ASSIGNOR T0 :BENDIX RESEARCH CORPO- RATION, OF SOUTH BEND, INDIANA, A CORPORATION OllJINDIA'NA` PROPELLER Application led .Tune 16, 1930. Serial No. 461,369.

This invention relates to propellers and more particularly to propellers for aircraft. An object of the invention is to provide a propeller in which the resistance or force imposed npon the propeller t'ends to decrease the pitch of the propeller blades.

Another object of the 'invention is to provide a propeller in which the resistance or force imposed on the propeller proportionally decreases the pitch of the blades of the propeller. Another object of the invention is to pro- 'vide a propeller in which each blade is free to find its own pitch within certain limits.

Another object of the invention is to provide a propeller in which each blade is free to iind its own pitch within a limited range and the change in the pitch of one blade reacts against the opposite blade so that the blades are differentiated or compensated.

A furtherobject of the invention is to provide a propeller 'having means for normally 'maintaining the blades thereof at the maximum pitch angle and permitting a variable pitch ofthe/blades proportioned to the resistance or force encountered.

A further object of the inventionis Vto provide a propeller in which the centrifugal force about the axis of rotation is balanced between the blades, so that only a small load may be imposed on the bearings on which the blades revolve on their longitudinal axes.

A further object of the invention is to provide a 'propeller in which the center of pressure of each blade is located'toward the trailing edge or awayv from the axis of rotation of the propeller, so that the pitch of the blades will vary pro ortionally to variations f in the resistancefor orce encountered.

Other objects andthe structural details will appear' from the subjoined description taken in connection with the accompanying drawings, in which:

Figure 1 is a front elevation of a propeller embodying the invention;

Figure 2 is a vertical sectional view through the hub of the propeller;

Figure 3 is a sectional view substantially on line 3 3, Figurej;

Figure 4 is a perspective view of one of the anchor members; f

Figure 5 is asectional view of a Inodiication of the propeller; i

Figure 6 is a sectional view substantially on 1i-neA 6-6, Figure n 5 and Figure 7 is'a sectional Iview of another modification.

Referring to the drawings for more specific details of the invention, 10 represents a.y crank shaft of an internal combustion engine. A propeller hub 1l is lixedly secured (in the shaft.4 Asshowin the hub is formed in two parts, secured together as by clamps l2. The parts when assembled provide a cylindrical body 13 having a lateral sleeve 14 adapted to lit on the shaft 10 and diametin the .enlarged diametral portion with av ball bearing 26 fitted on the sleeve and. clamped in position between the extreme end of the shank and the flange. Positioned on the shank and bearing against the shoul-l ders 2l is a ball bearing 27. This bearing is secured against displacement by a retaining nut 28 threaded in the end ,of the sleeve in which. the shank of the propeller vis positioned and the clamp 12 is' threaded onI the sleeve over the retaining'nut. Thebearings 26 and 27 suitably support the propellers for rotation upon. their longitudinal axes within a range limited by av suitable 4stop 30 on the clamp and a pin 31 e on the/shank. Other means for'limiting the movement of the propellers on their longitudinal axes may be provided. Fositioned in 'each of the sleeves 15 and 16 is an anchor member 32. As shown, the anchor member comprises a sleeve 33 having a flange 34 splined as indicated at 35 and a conical portion 36' terminating in a rectangular portion 37 slotted as indicated at 38 and provided with oppositely. disposed apertures 39, the object of which will hereinafter appear. f

The anchorlmembers are fitted in the Sleeves 15 and 16 inoppositely disposed relation with respect to each other. As shown7` the splines 35 on the anchors engage the splines in the sleeves and the anchors are ends of which are secured sleeves 24 retained in position by the sleeve 24 thread ed in the end of the shank and diametral bolts 39 and the anchor members.

The anchor members are secured together by a laminated leaf sprinol 40, the respective lar portions of the anchors as by bolts 41. This leaf spring serves to retain the blades of the propellers at the maximum pitch angle and the centrifugal force about the axis of rotation of the .propellers is balanced through the spring, thus leaving but a small load on the bearings 26 and 27. It willbe observed that each blade is free to find its own pitch within a limited range and that movement of one ofthe blades on its longitudinal axis reacts on the opposite blade and hence the blades are differentiated or compensated.

A modification of theinvention is illustrated in Figures 5 and 6. In this embodiin the rectangu' passing through the Shanks, the

I do not intend to-be limited to those shown,

except as such limitations are clearly im- 1 posed by the appended claims. e

Having thus described the various features of the invention, what I claim as-new and desire to secure by Letters Patent is:

1. A propeller comprising a hub having diametral sleeves, blades havingshanks positioned for rotation inthe sleeves, cone shaped anchors positioned in the s hanks in oppositely disposed relation with respect to each other, means securing the anchors to the Shanks and a laminated leaf spring connecting the anchors.

2. A propeller comprising a hub, a plurality of blades rotatably carried by said hub, a rotatable shaft for driving the hub,

lresilient members interconnecting the inner ment, two springs 42 connect the anchor members 82. Thesesprings are arranged in spaced relation, so that thedriving shaft may pass between them. This type is preferred vin instanceswhere the shaft 10 extends through the body of the propeller and in Figure 7, I have shown a further modification. In this embodiment, the spring 40 passes through a slot 43 in the propeller shaft.

It may be found desirable to provide an adjustable friction means for the blades and to that end friction blocks 44 are positioned in the sleeves 15 and 16 4in engagement with the Shanks 17 and 18 and these blocks are made adjustable through set screws 45 mounted in the wall of the sleeves, or other suitable adjustmentmeans may be employed. It will be observed that the center of pressure on each blade is located towards the trailing edge or away from the longitudinal axis ofthe blade so that air pressure acts against the spring and hence the greater the air pressure the' smaller theipitch of the blade.

It will also be observed that centrifugal force about the rotating axis of the propeller acts through the spring, so that at high speed, the pitch tends to decrease. It is apparent that in cases wherev it is desirable, the blades may be counterweighted to reduce the action of the centrifugal force about the invention and .since these may be lncorpoends of said blades andnormally maintaining said blades at a maximum pitch angle, said blades being supported forwardly of the center of pressure thereof to effecta reduction in pitch of the/blades in accordance with air resistance thereon during rotation.

3. A propeller comprising a hub, blades positioned for rotation thereon, a rotatable shaft, means for drivably connecting said hub and shaft, single means interconnecting the. blades to normally maintain .them at a maximum pitch angle, and means for decreasing the pitch of said blades in operation, said last-named means being operable in accordance with air resistance encountered by the blades.

4. A propeller comprising a hub, a plurality of blades rotatably carried by said hub, a rotatable shaft, means for drivably connecting the huband shaft, a laminated leaf spring interconnecting the inner ends of said blades interiorly of the hub for normally maintaining said blades at a maximum pitch angle, and'means for supporting said blades to ei'ect a reduction in the pitch thereof in response to air resistance during operation.

5. A propeller comprising a hub, a plurality of propeller blades rotatably supported therein, and torsionally resistant means interconnecting the root ends of said blades and normally maintaining the latter in such Vposition that the pitch thereof is a predetermined maximum, said blades being automatically rotatable about, their longitudinal axes in accordance with air resistance encountered thereby during operation of the propeller for decreasing the pitch thereof.

-ADIEL Y. DODGE. 

